Abstract

Reaction of BF3·OEt2 with 3 (BunLi·HMPA)[HMPA = OP(NMe2)3] has been monitored by variable-temperature 7Li and 11B n.m.r. spectroscopy and shown to produce a highly arene-soluble, crystalline complex, LiBF4·4HMPA, (1); spectroscopic, cryoscopic, and conductimetric measurements indicate that this exists in solution as tight lithium and tetrafluoroborate components held by Li F interactions.